David Spohn

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since Dec 22, 2015
Alberta, Canada
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Recent posts by David Spohn

Certainly a fascinating discussion. My sense of it is that while the technology has been around for quite a while, LEDs for use as lighting are still, relatively speaking, in their infancy.

Troy Rhodes wrote:They could even make leds that emit a color spectrum that is very similar to incandescent lighting.  As soon as the marketing people hear about this, you'll see led products come out with a much warmer color spectrum.



I think that's already well underway. Yuji is one company that makes a CRI 98 LED bulb. They show a chart on their site comparing its spectrum to daylight. It's interesting that they make the bulb not so much for health reasons but rather for better rendition of colours in store displays and so on.

http://www.yujiintl.com/high-cri-led-lighting

It should also be noted that when we talk about the daylight spectrum, that generally means high noon on clear day (near the equator I presume, perhaps at a certain altitude?). Sunlight changes over the course of the day, so I'm sure there's debate to be had over what colour temperatures are ideal for night time use. How about artificial lighting that mimicks the cycles of sunlight? Yep, someone is working on that too:

http://gizmodo.com/these-bulbs-mimic-the-sun-all-day-to-help-you-sleep-bet-1711988347
2 years ago
I think it's only a matter of time before we're using wind and solar power to produce (and maybe even transport, someday) more windmills and solar panels.
2 years ago
I can't speak for New England, but I don't doubt that small square bales suitable for building are getting harder to find in some areas. However, my understanding is that there are farmers who now make square bales specifically for construction, and some of them even store them in a shed so they're ready to go when you need them. Not sure how affordable they are, or whether you'd find something like that in your area.

As you mention, materials for clay straw or clay chip are probably easier to source, and it's probably less labour for a small crew. I don't see a lot of downsides to it, unless you want it done really fast, or you don't have time to let it dry before plastering.
2 years ago
I've seen plastic used under the sand, but I wouldn't recommend it as it tends to make the walkway less stable and it can trap moisture underneath the walkway and cause freezing expansion issues. A properly constructed brick or paver walkway will shed most of the water that hits it without additional waterproofing. Where they've sunk over the ages you will often see puddles forming on them. Some water will soak into the sand, but that will happen anyway if the plastic is under the sand. They actually make special "permeable" pavers that are designed to let water through for areas where drainage is a problem.

If I really wanted the pavement to be completely waterproof, I'd apply some sort of sealant after it was built, but of course, that usually involves plastic-like chemicals. This is most often done not so much to make the pavement waterproof as to protect it from stains caused by fluids leaking from vehicles.
2 years ago
Hi Ken,

I just noticed your post - I'm still a few years away from having the funds to get started, but it gives me plenty of time to learn and make plans. It'll be my first experience with SLC, so I'm sure I'll need all the help and advice I get if/when the time comes. Odds are it'll be in BC somewhere, but I'd also be interesting is getting some experience beforehand if circumstances allowed.

Cheers,

Dave
2 years ago

David, What ratio do you suggest for seed starting?



I'm sort of experimenting with some small lamps I found that are 2 red for each blue, but that's probably more blue than you need. I'd guess a 3 to 1 or even 4 to 1 ratio would work just as well, if not better. So a lamp designed for vegetative growth should do the trick. The tech is changing pretty fast, and some lamps now even have switches for vegetative and flowering modes.
2 years ago
I've been using LED grow lights of various kinds for over 5 years now, and they are revolutionizing artificial light for plants. One reason for this is that LEDs can focus specifically on the colours of light the plants need, and not waste power on other colours.

Colour temperature (measured in Kelvin) is less relevant to the discussion in the case of grow LEDs, because it applies mostly to hues of white light, akin to the sun. But photosynthesis doesn't use the whole spectrum (at least, not equally). It uses mostly red light, and some blue, and not much if any of the other colours, although I don't doubt that there's still some debate about the perfect combination, and that may also vary from one type of plant to the next. So, most LED grow lights appear red when you turn them on, and the vast majority use both red and blue LEDs, usually at a ratio of about 4 or 5 red for each blue. A light for vegetative growth typically has a higher ratio of blue than a flowering light, but it will still be mostly red. You can buy pure red and pure blue lamps, but they're intended to be used as supplementary lighting. Some companies are now putting a small amount of infra red, ultraviolet, or white into the mix, but I don't know if there's any science to justify it or whether it's just a gimmick.

What I've found is that lights with fewer, higher-powered LEDs are better than lights with more, lower-powered LEDs. That is, one 3W LED will serve you better than three 1W LEDs. This is especially true when it comes to lights made with individual LEDs that are less than 1W each, which, although they "work," seem to have relatively poor penetration.

I've never tried an LED replacement bulb in a T5 fixture, but I'd start by comparing the price of 6 LED bulbs with that of a new fixture. I've had pretty good luck ordering the stuff from China through eBay, as it all seems to come from there anyway, and there's very little available locally.
2 years ago
I think a flotation system would be very complicated, especially if you wanted to produce power on both the rise and fall of the tide. Using the float to compress air or water and force it through a hydraulic motor might require less engineering than using gears, but I suspect it would still be expensive and challenging to fabricate, and would probably require very large floats.

What might be cool, as Hans suggested, and if you had the ideal spot for it, would be some adaptation of the medieval tide mill approach - catching water at high tide and releasing it through a turbine at low tide.
2 years ago

when in the point mode the receiver does not work



Ah, that's a bummer. Good to know though. How about using it on it's back, just sitting on something flat rather than the tripod? Can the receiver mount be adjusted so it sits horizontally on the rod? I can't play with ours right now because it's in my partner's garage.

We use ours almost exclusively for shooting grade in landscape projects (paver installations, retaining walls, etc.) and they really are great tools for that, even though there is always an "analogue" way to get it done. It replaced an older-style transit, which was a 2 person job. I can imagine a few other things it would come it handy for, like building a foundation or a floor, but in general I'd say it's more about efficiency than necessity. Were I building a mid-size home (maybe someday) I'd keep it around, but I guess I'm a bit of a tool hound. Hope that helps.
2 years ago